Recent studies have indicated that sulfation plays a role in the inactivation of catecholamines and serotonin in the central and in the peripheral nervous systems. Studies are proposed to determine the importance of sulfation in the disposition of catecholamines and serotonin when competing enzymes (monoamine oxidase and, for the catecholamines, catechol-O-methyltransferase and dopamine-J- hydroxylase) are inhibited. These studies will be done in (a) in vivo ventriculocisternal perfusions in dog and (b) superfused slices of sympathetic ganglia from the lumbar region in dogs. Concentrations of endogenous free and conjugated amines and of their acid metabolites will be measured in perfusates using high performance liquid chromatography with electrochemical detection. We also propose to determine whether in the dog, conjugated amines are transported from CSF to blood by a probenecid-sensitive active transport. Finally, it has been suggested that sulfated amines in plasma act as storage forms from which free amines can be generated. Studies are proposed to ascertain whether desulfation of sulfated amines occurs in the isolated perfused rat liver system.